Transport stream generating device, transmitting device, receiving device, and a digital broadcast system having the same, and method thereof

ABSTRACT

A transport stream (TS) generating apparatus, a transmitting apparatus, a receiving apparatus, a digital broadcast system having the above, and a method thereof are provided. The digital broadcast system includes a transport stream (TS) generating apparatus which generates a multi transport stream (TS) by multiplexing a normal stream and a turbo stream having a variable coding rate, a transmitting apparatus which re-constructs the multi TS by processing the turbo stream, and transmits the re-constructed multi TS, and a receiving apparatus which receives the re-constructed multi TS, and decodes the normal stream and the turbo stream respectively, to recover normal data and turbo data. Accordingly, a multi TS, which includes normal stream and a turbo stream of various coding rates, can be transmitted and received efficiently.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 12/021,521filed on Jan. 29, 2008, now U.S. Pat. No. 8,149,932 which claims thebenefit of Korean Application No. 2007-38947 filed Apr. 20, 2007, in theKorean Patent Office, the disclosures of which are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Aspects of the present invention relate to a transport stream (TS)generating device, a transmitting device, a receiving device, a digitalbroadcast system having the same, and a method thereof. Moreparticularly, aspects of the present invention relate to a transportstream (TS) generating device, a transmitting device, a receivingdevice, a digital broadcast system having the same, and a methodthereof, in which power consumption of the receiving device of an ATSCVSB system is reduced, and multi TS including turbo stream and normalstream of various coding rates is transmitted and received.

2. Description of the Related Art

An ATSC VSB digital broadcast system adopts a field sync signal in theunit of 312 segments. Therefore, reception degrades in the poor channelsuch as a Doppler fading channel.

FIG. 1 is a block diagram of a conventional ATSC DTV transmitter andreceiver. The ATSC VSB system uses a dual transport stream (TS) whichincludes normal data and turbo data added to normal data.

Referring to FIG. 1, a digital broadcast transmitter performs errorcorrection encoding of dual TS. Accordingly, the digital broadcasttransmitter includes a randomizer 11 to randomize a dual TS, aReed-Solomon (RS) encoder 12 of concatenated coder type to correct anerror generated during the transmission process due to a channelcharacteristic, an interleaver 13 to interleave RS-encoded data, and atrellis encoder 14 to map, by trellis encoding at the rate of 2/3, theinterleaved data into 8-level symbol.

A digital broadcast receiver includes a multiplexer 15 to insert fieldsync and segment sync into error-corrected data to form the data formatillustrated in FIG. 2, and a modulator 16 to add a DC value to a datasymbol which has the field sync and segment sync inserted therein,insert a pilot tone, perform pulse-shape and VSB modulation, convert thesignal into a signal in RF channel band, and send out the signal.

Accordingly, a digital broadcast transmitter and receiver adopting adual TS scheme multiplexes normal data and turbo data and inputs themultiplexed data to the randomizer 11.

The input data is randomized at the randomizer 11, and the randomizeddata is outer-coded at the RS encoder 12 employed as an outer coder. Thecoded data is rearranged at the interleaver 13.

The interleaved data is inner-coded at the Trellis encoder 14 based onthe 12 symbol units, and the inner-coded data is mapped to 8-levelsymbols. Field sync and segment sync are inserted, and then pilot tonesare inserted. The data is converted into RF signal by VSB modulation andforwarded.

Referring to FIG. 1, the digital broadcast receiver includes a tuner(not shown) to convert the RF signal received through a channel into abaseband signal, a demodulator 21 to perform synchronization detectionand demodulation of the converted baseband signal, an equalizer 22 tocompensate for multipath channel distortion of the demodulated signal, aviterbi decoder 23 to correct the error of the equalized signal anddecode into symbol data, a deinterleaver 24 to rearrange the interleaveddata from the interleaver 13 of the digital broadcast transmitter, a RSdecoder 25 to correct the error, and a derandomizer 26 to derandomizethe corrected data from the RS decoder 25 and to output MPEG-2 transportstream.

As explained above, the digital broadcast receiver of FIG. 1down-converts the RF signal into baseband, by the processing performedin reverse order to that at the digital broadcast transmitter. Thedigital broadcast receiver then demodulates and equalizes the convertedsignal, and performs channel decoding to recover the original signal.

FIG. 2 illustrates a VSB data frame of a U.S-oriented digital broadcast(8-VSB) system in which segment sync and field sync are inserted. Asillustrated, one frame includes two fields, and one field includes onefield sync segment in the first segment, and 312 data segments. Onesegment of a VSB data frame corresponds to one MPEG-2 packet, and onesegment includes four symbol segment sync and 828 data symbols.

Referring to FIG. 2, segment sync and field sync are used at a digitalbroadcast receiver for synchronization and equalization. Field sync andsegment sync are data previously known to a digital broadcasttransmitter and a digital broadcast receiver, and used as a referencesignal during equalization by the digital broadcast receiver.

Variable coding rates may be applied to turbo data depending onbroadcast programs, and the turbo data may be included in dual TS.Accordingly, dual TS may be generated, including normal data and turbodata of various coding rates.

However, a conventional digital broadcast system does not providetransmission and reception of dual TS including normal data and turbodata of various coding rates.

Accordingly, a digital broadcast system is required, which is capable ofprocessing transmission and reception of dual TS including normal dataand turbo data of various coding rates.

SUMMARY OF THE INVENTION

Aspects of the present invention provide a transport stream (TS)generating apparatus, a transmitting apparatus, a receiving apparatus, adigital broadcast system having the same, and a method thereof, which iscapable of transmitting and receiving multi TS including normal streamand turbo stream of various coding rates, and reducing power consumptionof a receiver of an ATSC VSB system.

According to an aspect of the present invention, there is provided adigital broadcast system, which may include a transport stream (TS)generating apparatus which generates a multi transport stream (TS) bymultiplexing a normal stream and a turbo stream having a variable codingrate, a transmitting apparatus which re-constructs the multi TS byprocessing the turbo stream, and transmits the re-constructed multi TS,and a receiving apparatus which receives the re-constructed multi TS,and decodes the normal stream and the turbo stream respectively, torecover normal data and turbo data.

According to an aspect of the present invention, the TS generatingapparatus may include a Reed-Solomon (RS) encoder which externallyreceives a turbo stream, and RS encoder which encodes the turbo stream,a duplicator which prepares a parity insertion region according to thevariable coding rate, with respect to the RS-encoded turbo stream, and amultiplexer (MUX) which externally receives a normal stream, andmultiplexes the turbo stream processed at the duplicator along with thenormal stream, to generate the multi TS.

According to an aspect of the present invention, the transmittingapparatus and the receiving apparatus may perform signal processing ofthe turbo stream based on a predetermined packet unit, the predeterminedpacket unit being a multiple of 52 packets.

According to an aspect of the present invention, the transmittingapparatus may include a randomizer which receives the multi TS from theTS generating apparatus and randomizes the received multi TS, a turboprocessor which re-constructs the multi TS by detecting the turbo streamfrom the randomized multi TS and encoding the detected turbo stream,outer-interleaving the encoded turbo stream, deinterleaving in a mannercorresponding to the interleaving, and inserting the deinterleavedresult into the multi TS, a Reed-Solomon (RS) encoder which RS encodesthe re-constructed multi TS, a data interleaver which interleaves theencoded multi TS, a trellis encoder which trellis encodes theinterleaved multi TS, a multiplexer (MUX) which carries out multiplexingby adding a synchronous signal to the trellis-encoded multi TS, and amodulator which channel-modulates the multiplexed multi TS, up-convertsthe channel-modulated multiplexed multi TS into an RF channel bandsignal, and transmits the resultant signal.

According to an aspect of the present invention, the receiving apparatusmay include a demodulator which receives the transmitted multi TS anddemodulates the received signal, an equalizer which equalizes thedemodulated multi TS, a first processor which processes the normalstream of the equalized multi TS to recover normal data, and a secondprocessor which performs decoding of the turbo stream of the equalizedmulti TS according to the coding rate of the turbo stream, to recoverturbo data.

According to an aspect of the present invention, the second processormay include a turbo decoder which performs turbo-decoding according tothe coding rate of the turbo stream of the equalized multi TS, a secondderandomizer which derandomizes the multi TS including the turbo-decodedturbo stream, and a turbo stream detector which detects the turbo streamfrom the derandomized multi TS, to recover the turbo data.

According to another aspect of the present invention, there is provideda transport stream (TS) generating apparatus, which may include aReed-Solomon (RS) encoder which externally receives a turbo stream, andan RS encoder encodes the turbo stream, a duplicator which prepares aparity insertion region in the RS encoded turbo stream according to avariable coding rate, and a multiplexer (MUX) which externally receivesa normal stream, and multiplexes the turbo stream processed at theduplicator along with the normal stream, to generate a multi transportstream (TS).

According to an aspect of the present invention, the duplicator mayconvert each byte of the turbo stream according to coding ratesincluding 1/2, 1/4, 3/4, 5/6, and 7/8 rates, to prepare the parityinsertion region between data bits of the turbo stream.

According to an aspect of the present invention, the TS generatingapparatus may further include a randomizer which randomizes thegenerated multi TS, a turbo processor which re-constructs the multi TSby detecting the turbo stream from the randomized multi TS and encodingthe detected turbo stream, outer-interleaving the encoded turbo stream,deinterleaving in a manner corresponding to the interleaving, andinserting the deinterleaved result into the multi TS, and a derandomizerwhich derandomizes the multi TS processed at the turbo processor.

According to an aspect of the present invention, the turbo processor mayinclude a turbo stream detector which detects the turbo stream from therandomized multi TS, an outer encoder which inserts a paritycorresponding to the detected turbo stream into a parity insertionregion prepared in the turbo stream, an outer interleaver whichouter-interleaves the parity-inserted turbo stream, a data deinterleaverwhich deinterleaves the interleaved turbo stream, and a turbo streamstuffer which re-constructs the multi TS by inserting the deinterleavedturbo stream into the multi TS.

According to yet another aspect of the present invention, there isprovided a transmitting apparatus, which may include a randomizer whichreceives a multi transport stream (TS), including a mixture of a normalstream and a turbo stream having a variable coding rate, from the TSgenerating apparatus and randomizes the received multi TS, a turboprocessor which re-constructs the multi TS by detecting the turbo streamfrom the randomized multi TS and encoding the detected turbo stream,outer-interleaving the encoded turbo stream, deinterleaving in a mannercorresponding to the interleaving, and inserting the deinterleavedresult into the multi TS, a Reed-Solomon (RS) encoder which RS encodesthe re-constructed multi TS, a data interleaver which interleaves theencoded multi TS, a trellis encoder which trellis encodes theinterleaved multi TS, a multiplexer (MUX) which carries out multiplexingby adding a synchronous signal to the trellis-encoded multi TS, and amodulator which channel-modulates the multiplexed multi TS, up-convertsthe channel-modulated multiplexed multi TS into RF channel band signal,and transmits the resultant signal.

According to an aspect of the present invention, the transmittingapparatus may further include a parity region generator provided at afront end of the turbo processor, and which generates a parity insertionregion with respect to the randomized multi TS, a data interleaver whichinterleaves the multi TS having the parity insertion region, and a datadeinterleaver provided before the turbo processor, and whichdeinterleaves the re-constructed multi TS.

According to an aspect of the present invention, the RS encoder maycarry out encoding by adding a parity corresponding to the multi TS to aparity insertion region generated by the parity region generator.

According to yet another aspect of the present invention, there isprovided a receiving apparatus, which may include a demodulator whichreceives a multi transport stream (TS), including a normal stream and aturbo stream having a variable coding rate, and demodulates the receivedsignal, an equalizer which equalizes the demodulated multi TS, a firstprocessor which processes the normal stream of the equalized multi TS torecover normal data, and a second processor which performs decoding ofthe turbo stream of the equalized multi TS according to the coding rateof the turbo stream, to recover turbo data.

According to an aspect of the present invention, the second processormay include a turbo decoder which performs turbo-decoding according tothe coding rate of the turbo stream of the equalized multi TS, a secondderandomizer which derandomizes the multi TS including the turbo-decodedturbo stream, and a turbo stream detector which detects the turbo streamfrom the derandomized multi TS, to recover the turbo data.

According to an aspect of the present invention, the turbo decoder mayinclude a trellis map decoder which trellis-decodes the turbo stream ofthe equalized multi TS, an outer deinterleaver which outer-deinterleavesthe trellis-decoded turbo stream, an outer map decoder whichouter-decodes the deinterleaved turbo stream, and an outer interleaverwhich interleaves the turbo stream being decoded at the outer mapdecoder and provides the trellis decoder with the resultant signal, if asoft decision is output from the outer map decoder.

According to yet another aspect of the present invention, there isprovided a digital broadcast method, which may include generating amulti transport stream (TS) by multiplexing a normal stream and a turbostream having a variable coding rate, re-constructing the multi TS byprocessing the turbo stream, and transmitting the re-constructed multiTS, and receiving the re-constructed multi TS, and decoding the normalstream and the turbo stream respectively, to recover normal data andturbo data.

According to an aspect of the present invention, the generating of themulti TS may include externally receiving a turbo stream, andReed-Solomon (RS) encoding the turbo stream, preparing a parityinsertion region according to the variable coding rate, with respect tothe RS-encoded turbo stream, and externally receiving a normal stream,and multiplexing the processed turbo stream along with the normalstream, to generate the multi TS.

According to an aspect of the present invention, the transmitting of themulti TS may include receiving the generated multi TS and randomizingthe received multi TS, re-constructing the multi TS by detecting theturbo stream from the randomized multi TS and encoding the detectedturbo stream, outer-interleaving the encoded turbo stream,deinterleaving in a manner corresponding to the interleaving, andinserting the deinterleaved result into the multi TS, Reed-Solomon (RS)encoding the re-constructed multi TS, interleaving the encoded multi TS,trellis encoding the interleaved multi TS, multiplexing by adding asynchronous signal to the trellis-encoded multi TS, andchannel-modulating the multiplexed multi TS, up-converting thechannel-modulated multiplexed multi TS into an RF channel band signal,and transmitting the resultant signal.

According to an aspect of the present invention, the receiving of themulti TS may include receiving the transmitted multi TS and demodulatingthe received signal, equalizing the demodulated multi TS,first-processing the normal stream of the equalized multi TS to recovernormal data, and second processing by decoding the turbo stream of theequalized multi TS according to the coding rate of the turbo stream, torecover turbo data.

According to an aspect of the present invention, the second processingmay include turbo-decoding according to the coding rate of the turbostream of the equalized multi TS, derandomizing the multi TS includingthe turbo-decoded turbo stream, and detecting the turbo stream from thederandomized multi TS, to recover the turbo data.

According to yet another aspect of the present invention, there isprovided a transport stream (TS) generating method, which may includeexternally receiving a turbo stream, and Reed-Solomon (RS) encoding theturbo stream, preparing a parity insertion region in the RS encodedturbo stream according to a variable coding rate, and externallyreceiving a normal stream, and multiplexing the processed turbo streamalong with the normal stream, to generate a multi transport stream (TS).

According to an aspect of the present invention, the preparing theparity insertion region may include converting each byte of the turbostream according to coding rates including 1/2, 1/4, 3/4, 5/6, and 7/8rates, to prepare the parity insertion region between data bits of theturbo stream.

According to an aspect of the present invention, the TS generatingmethod may further include randomizing the generated multi TS,re-constructing the multi TS by detecting the turbo stream from therandomized multi TS and encoding the detected turbo stream,outer-interleaving the encoded turbo stream, deinterleaving in a mannercorresponding to the interleaving, and inserting the deinterleavedresult into the multi TS, and derandomizing the multi TS having theturbo stream inserted therein.

According to an aspect of the present invention, the re-constructing ofthe multi TS may include detecting the turbo stream from the randomizedmulti TS, inserting a parity corresponding to the detected turbo streaminto a parity insertion region prepared in the turbo stream,outer-interleaving the parity-inserted turbo stream, deinterleaving theinterleaved turbo stream, and re-constructing the multi TS by insertingthe deinterleaved turbo stream into the multi TS.

According to yet another aspect of the present invention, there isprovided a transmitting method, which may include receiving a multitransport stream (TS), including a mixture of a normal stream and aturbo stream having a variable coding rate, and randomizing the receivedmulti TS, re-constructing the multi TS by detecting the turbo streamfrom the randomized multi TS and encoding the detected turbo stream,outer-interleaving the encoded turbo stream, deinterleaving in a mannercorresponding to the interleaving, and inserting the deinterleavedresult into the multi TS, Reed-Solomon (RS) encoding the re-constructedmulti TS, interleaving the encoded multi TS, trellis encoding theinterleaved multi TS, multiplexing by adding a synchronous signal to thetrellis-encoded multi TS, and channel-modulating the multiplexed multiTS, up-converting into RF channel band signal, and transmitting theresultant signal.

According to an aspect of the present invention, the transmitting methodmay further include generating a parity insertion region with respect tothe randomized multi TS, and interleaving the multi TS having the parityinsertion region.

According to an aspect of the present invention, the transmitting methodmay further include deinterleaving the re-constructed multi TS.

According to an aspect of the present invention, the RS encoding mayinclude adding a parity corresponding to the multi TS to the generatedparity insertion region.

According to yet another aspect of the present invention, there isprovided a receiving method, which may include receiving a multitransport stream (TS), including a normal stream and a turbo streamhaving a variable coding rate, and demodulating the received signal,equalizing the demodulated multi TS, first processing the normal streamof the equalized multi TS to recover normal data, and second processingdecoding of the turbo stream of the equalized multi TS according to thecoding rate of the turbo stream, to recover turbo data.

According to an aspect of the present invention, the second processingmay include turbo-decoding according to the coding rate of the turbostream of the equalized multi TS, derandomizing the multi TS includingthe turbo-decoded turbo stream, and detecting the turbo stream from thederandomized multi TS, to recover the turbo data.

According to an aspect of the present invention, the turbo-decoding mayinclude trellis-decoding the turbo stream of the equalized multi TS,outer-deinterleaving the trellis-decoded turbo stream, outer-decodingthe deinterleaved turbo stream, and interleaving the outer-decoded turbostream and trellis decoding the resultant signal, if a soft decision isoutput from the outer decoding.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be obviousfrom the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a block diagram of a conventional Advanced Television SystemsCommittee (ATSC) vestigial sideband (VSB) system;

FIG. 2 is a view illustrating an exemplary structure of a conventionalATSC VSB data frame;

FIG. 3 is a block diagram of a digital broadcast system according to anexemplary embodiment of the present invention;

FIG. 4 is a block diagram of a transport stream (TS) generatingapparatus of FIG. 3 according to an exemplary embodiment of the presentinvention;

FIG. 5 is a view illustrating the structure of a multi transport stream(TS) according to an exemplary embodiment of the present invention;

FIG. 6 is a block diagram of a transmitting apparatus of FIG. 3according to an exemplary embodiment of the present invention;

FIG. 7 is a block diagram of the turbo processor of FIG. 6;

FIG. 8 is a block diagram of a transmitting apparatus according toanother exemplary embodiment of the present invention;

FIG. 9 is a block diagram of the turbo processor of FIG. 8;

FIG. 10 is a block diagram of a transport stream (TS) generatingapparatus according to another exemplary embodiment of the presentinvention;

FIG. 11 is a block diagram of a transport stream (TS) generatingapparatus according to yet another exemplary embodiment of the presentinvention;

FIG. 12 is a block diagram of a transmitting apparatus according to yetanother exemplary embodiment of the present invention;

FIG. 13 is a block diagram of the receiving apparatus of FIG. 3according to an exemplary embodiment of the present invention;

FIG. 14 is a block diagram of the turbo decoder of FIG. 13;

FIG. 15 is a flowchart illustrating the process of transmitting multi TSaccording to an exemplary embodiment of the present invention;

FIG. 16 is a flowchart illustrating the turbo processing according to anexemplary embodiment of the present invention;

FIG. 17 is a flowchart illustrating the process of receiving multi TSaccording to an exemplary embodiment of the present invention; and

FIG. 18 is a flowchart illustrating the turbo-decoding process accordingto an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below in order to explain thepresent invention by referring to the figures.

FIG. 3 is a block diagram of a digital broadcast system according to anexemplary embodiment of the present invention.

Referring to FIG. 3, a digital broadcast system includes a transportstream (TS) generating apparatus 100, a transmitting apparatus 200 and areceiving apparatus 300.

The TS generating apparatus 100 receives normal stream and turbo streamhaving variable coding rate, and generates a multi TS by multiplexingthe received data. FIG. 4 is a block diagram of an exemplary structureof the TS generating apparatus 100.

Referring to FIG. 4, the multi TS generating apparatus 100 includes aReed Solomon (RS) encoder 110, a duplicator 120, and a multiplexer (MUX)130.

The RS encoder 110 receives turbo stream, adds parities, encodes theparity-added stream, and provides the duplicator 120 with the signal.

The RS encoder 110 removes synchronous signal from the turbo stream,computes parities regarding the turbo stream region, and adds 20-bytelong parities.

As a result, one packet of the final form of the turbo stream after theencoding includes a total of 207 bytes. Three out of 207 bytes areallocated to packet identity (PID), 184 are allocated to turbo data, and20 are allocated to parities.

The duplicator 120 prepares a parity insertion region in the encodedturbo stream, according to the variable coding rates.

Accordingly, the duplicator 120 prepares a parity insertion regionbetween data bits of the turbo stream, by changing each byte of theturbo stream according to various coding rates such as 1/2, 1/4, 3/4,5/6, or 7/8.

The above process of preparing a parity insertion region will beexplained in greater detail below. Each byte of the turbo stream, whichis the basic unit of the turbo stream, is divided into one to sevenbytes according to coding rates. A part of one-byte bit value and nulldata (for example, 0) are then stuffed in each byte. The region wherethe null data is stuffed, becomes a parity insertion region.

The operation of the duplicator 120 will be explained in greater detailbelow.

If bits included in one byte are represented as ‘a, b, c, d, e, f, g, h’from the most significant bit (MSB), and if a signal is input in thesame order, an output from the duplicator 120 may be doubled by 1/2coding rate and represented as ‘a, a, b, b, c, c, d, d, e, e, f, f, g,g, h, h.’

Starting from the MSB, total two bytes, including 1 byte represented as‘a, a, b, b, c, c, d, d’ and another 1 byte represented as ‘e, e, f, f,g, g, h, h’ are sequentially output.

If the input is quadrupled by applying 1/4 coding rate, the output ofthe duplicator 120 may be represented as ‘a, a, a, a, b, b, b, b, c, c,c, c, d, d, d, d, e, e, e, e, f, f, f, f, g, g, g, g, h, h, h, h.’Accordingly, four bytes are output.

The duplicator 120 may not necessarily copy the input bits. Instead, theduplicator 120 may insert other value such as null data except thelocations previously designated.

For example, if the duplicator 120 doubles the input according to 1/2coding rate, the first bits of the pairs of consecutive bits may bemaintained, while the second bits of the pairs are replaced by anothervalue (x). Accordingly, ‘a, x, b, x, c, x, . . . ’ may be output,instead of ‘a, a, b, b, c, c, . . . .’

The size of input may be changed by other coding rates in the samemanner explained above.

Meanwhile, a data interleaver (not shown) may be inserted between the RSencoder 110 and the duplicator 120.

The MUX 130 prepares an adaptation field in each packet of the multi TS.The adaptation field is provided to insert turbo stream or other data.

In particular, the adaptation field includes an adaptation field header,and an insertion area. The insertion area is provided to insert otherdata.

A private data flag may be used as an insertion area. The adaptationfield header represents the length of an adaptation field and a flagwithin the adaptation field. The adaptation field header is the areacorresponding to the two bytes following the PID.

Accordingly, the MUX 130 may prepare an area to insert the turbo streamin a stuffing region of the adaptation field of the multi TS.Alternatively, the turbo stream may be inserted in the private data flagof the adaptation field.

The adaptation field may be used as an option field in which variouspacket information is written. The packet information may includeprogram clock reference (PCR) which is used for synchronization with thedemodulator of a receiver, original program clock reference (OPCR) whichis used for program recording, reservation and playback by the receiver,splice countdown, which are the consecutive numbers of macro blocksincluding four circuit blocks, one Cr block, and one Cb block, transportprivate data length which is the length of the text data of textbroadcast, and adaptation field extension length.

The area where the turbo stream is written, and the option field arearranged in a non-overlapping manner.

Meanwhile, in order to transmit turbo streams of various coding ratesand various data rates, the MUX 130 may generate multi TS havingdifferent coding rates based on the turbo unit. The ‘turbo unit’ isdesirably based on the multiples of 52 packets.

FIG. 5 illustrates the structure of a multi TS being output through theMUX 130 of FIG. 4. Referring to FIG. 5, a VSB data frame includes 312packets. For example, a VSB data frame includes 6 turbo units, eachturbo unit including 52 packets.

More specifically, one multi TS packet including a mixture of turbostream and normal stream form one frame with three multi TS packetsincluding normal stream only. Therefore, thirteen frames represent oneturbo unit.

In other words, 52 packets constitute one turbo unit, according to whichturbo stream is inserted alternately, in every fourth packet. The amountof turbo stream being inserted influences the data rate of the normalstream and the turbo stream.

Each of the six turbo units may include turbo stream of varying codingrates being inserted therein.

For example, ‘turbo 1’ denotes data packet of program 1, which includes1/2 rate-applied turbo stream. ‘Turbo 2’ denotes data packet of program2, which includes 1/4 rate-applied turbo stream.

Accordingly, ‘turbo 3’ and ‘turbo 4’ denote data packets of program 3,which include 1/2 rate-applied turbo stream. ‘Turbo 5’ and ‘turbo 6’denote data packet of program 4, which includes 1/4 rate-applied turbostream.

The above coding information and program information may be inserted inevery field, or inserted differently in each field. That is, whichcoding information and program information are inserted in each field,may be determined according to user design. The coding and programinformation is used at the receiving side.

The coding information, including the coding rate applied to therespective turbo streams, may be inserted in the synchronous signal ofthe multi TS. Alternatively, the coding information may be inserted in apart of data area of each packet. The ways to insert the codinginformation may be varied according to the specification by a designer,and not to be limited to certain examples.

Accordingly, a transmitting apparatus 200 is capable of performingencoding according to the coding rate indicated by the codinginformation.

If multi TS of the same construction is inserted in every VSB dataframe, the data rate of each stream determines the amount of coding rateand amount of turbo stream being inserted.

The transmitting apparatus of FIG. 3 may be constructed as illustratedin FIG. 6.

Referring to FIG. 6, the transmitting apparatus 200 includes arandomizer 210, a turbo processor 220, an RS encoder 230, a datainterleaver 240, a trellis encoder 250, a MUX 270 and a modulator 270.

The randomizer 210 randomizes the multi TS being received from the TSgenerating apparatus 100.

The turbo processor 220 exclusively detects turbo stream of therandomized multi TS, and robust-processes the detected turbo stream byencoding and interleaving.

The robust-processed turbo stream is deinterleaved, and inserted in themulti TS to re-construct a multi TS. The exemplary structure of theturbo processor 220 is illustrated in FIG. 7.

Referring to FIG. 7, the turbo processor 220 includes a turbo streamdetector 221, an outer encoder 223, an outer interleaver 225, a datadeinterleaver 227, and a turbo stream stuffer 229.

The turbo stream detector 221 exclusively detects the turbo stream fromthe randomized multi TS.

The outer encoder 223 encodes the detected turbo stream.

That is, the encoding includes the process of convolution-encoding theturbo stream, and inserting the encoded result in the parity insertionregion provided in the turbo stream. The encoding may be performed basedon the coding information inserted in the synchronous signal or the dataarea.

The outer interleaver 225 outer-interleaves the turbo stream encoded inthe turbo units, in which each turbo unit includes 52 packets.

The outer interleaver 225 interleaves according to a predeterminedinterleaving rule. For example, if ABCD is input in sequence, under theinterleaving rule of {2, 1, 3, 0}, the data is interleaved to DBAC andoutput. The interleaving rule may be varied according to thespecification by a designer.

The outer interleaver 225 has a similar structure to that of the outerdeinterleaver 420 provided in the turbo decoder 341 of the receivingapparatus 300. The term ‘outer interleaving’ includes interleavingprocess required for the turbo-decoding of turbo stream.

The data deinterleaver 227 deinterleaves the interleaved turbo stream.The data deinterleaver 227 processes turbo stream in reverse manner withrespect to the data interleaver 240 of FIG. 6.

The data deinterleaver 227 may also perform position exchange betweenturbo streams, and delay of turbo streams.

The deinterleaving of the data performed at the data deinterleaver 227is such that the multi TS being interleaved at the data interleaver 240of FIG. 6 has the structure in which the turbo stream is combined,enabling processing of turbo stream in turbo units as illustrated inFIG. 5.

Because turbo stream is processed in turbo units, processing time of theturbo decoder is reduced, and power consumption is reduced.

For example, if a user wants to watch program 2 only, turbo 2 isexclusively operated, without operating the other parts to process allthe other data. As a result, power consumption is reduced.

The turbo stream stuffer 229 inserts deinterleaved turbo stream in multiTS, to re-construct a multi TS. Accordingly, only the turbo stream canbe robust-processed, without having to process the entire multi TS.

Although not illustrated in the drawings, a byte-symbol converter (notshown), and a symbol-byte converter (not shown) may be additionallyprovided at a front end and a back end of the turbo processor.

The byte-symbol converter (not shown) and the symbol-byte converter (notshown) convert the multi TS from byte unit to symbol unit, or viceversa. The byte-to-symbol and symbol-to-byte conversion can be referredin table D5.2 of the American Television Systems Committee (ATSC)digital television (DTV) standards (A/53).

Referring back to FIG. 6, the RS encoder 230 RS-encodes the processedmulti TS.

The data interleaver 240 interleaves the encoded multi TS. That is, thedata interleaver 240 interleaves the multi TS according to interleavingrule under VSB standards.

The trellis encoder 250 trellis-encodes the interleaved multi TS.

The MUX 260 multiplexs the trellis-encoded multi TS, by adding segmentsync and field sync.

The modulator 270 channel modulates the multiplexed multi TS,up-converts the channel modulated multiplexed multi TS into RF channelband signal, and transmits the resultant signal to a receivingapparatus. The multi TS being transmitted from the modulator 270 isreceived at the receiving apparatus 300 through a channel.

Although not illustrated in the drawings, the modulator 270 may furtherinclude a pilot inserter (not shown), a pre-equalizer (not shown), a VSBmodulator (not shown), and a RF modulator (not shown).

The pilot inserter inserts a pilot, by adding a DC value to synchronoussignal-added multi TS.

The pre-equalizer equalizes the pilot-inserted multi TS, to minimizeinter-symbol interference.

The VSB modulator VSB modulates the equalized multi TS.

The RF modulator modulates the VSB-modulated multi TS into the RFchannel band signal, and transmits the signal.

Although the transmitting apparatus 200 according to the exemplaryembodiment of the present invention has the turbo processor 220 providedin back of the randomizer 210, the position of the randomizer 210 andthe turbo processor 220 may be exchanged.

In the event that the TS generating apparatus of FIG. 10 is combinedwith the transmitting apparatus of FIG. 12, the randomizer 210 and theturbo processor 220 exchange positions.

FIG. 8 is a block diagram of a transmitting apparatus according toanother exemplary embodiment of the present invention.

Referring to FIG. 8, the transmitting apparatus includes a randomizer210, a parity region generation unit 280, a first data interleaver 285,a turbo processor 290, a data deinterleaver 295, an RS encoder 230, asecond data interleaver 240, a trellis encoder 250, a MUX 260 and amodulator 270.

The randomizer 210 randomizes a multi TS being received from a TSgenerating apparatus 100 and provides the parity region generator 280with the resultant signal.

The parity region generator 280 prepares a region for parity insertion,in the multi TS including normal stream and turbo stream. Accordingly, aparity bit, being computed from the multi TS, is inserted, that is,written in the parity insertion region.

The first data interleaver 285 interleaves the multi TS being processedat the parity region generator 280.

The turbo processor 290 carries out turbo encoding by demultiplexing theinterleaved multi TS, detecting the turbo stream to encode the stream inturbo units, and multiplexing the turbo stream with the multi TS.

The exemplary structure of the turbo processor 290 is illustrated inFIG. 9. Referring to FIG. 9, the turbo processor 290 includes a DEMUX291, an outer encoder 223, an outer interleaver 225, and a MUX 293.

The DEMUX 291 detects turbo stream by demultiplexing the interleavedmulti TS.

The outer encoder 23 encodes the turbo stream in turbo units, bycomputing parities of the detected turbo stream, and inserting theparities in the parity insertion region of the turbo stream. The outerencoder 223 may perform encoding based on the coding information.

The outer interleaver 225 outer-interleaves the encoded turbo stream.

The MUX 293 multiplexes the interleaved turbo stream and the multi TS.As a result, the turbo stream is robust-processed.

The turbo processor 290 may be replaced with the turbo processor 220illustrated in FIG. 7. In this case, because the turbo stream of themulti TS being distributed by the second data interleaver 240 combineswith other turbo streams, the operation based on turbo units ispossible.

Referring back to FIG. 8, the data deinterleaver 295 deinterleaves themulti TS being output from the turbo processor 290.

The RS encoder 230 carries out encoding, by adding parities to the multiTS being provided by the data deinterleaver 295. In particular, the RSencoder 230 inserts parities computed based on the multi TS, into theparity insertion region prepared by the parity region generator 280.

The second data interleaver 240 interleaves the parity-added multi TS.

The trellis encoder 250 trellis encodes the multi TS being interleavedby the second data interleaver 240.

The MUX 260 carries out multiplexing, by adding segment sync and fieldsync to the trellis-encoded multi TS.

The modulator 270 channel modulate the multiplexed multi TS andup-converts into RF band signal.

FIG. 10 is a block diagram of a TS generating apparatus according toanother exemplary embodiment of the present invention.

Referring to FIG. 10, the TS generating apparatus includes a RS encoder110, a duplicator 120, an outer encoder 140, an outer interleaver 150, adata deinterleaver 160, and a MUX 130.

Meanwhile, the outer encoder 140, the outer interleaver 150, and thedata deinterleaver 160 may operate in the same manner as the outerencoder 223, the outer interleaver 225 and the data deinterleaver 227 ofFIG. 7. The explanation regarding overlapping elements or operationswill be omitted for the sake of brevity.

The RS encoder 110 removes synchronous signal from the turbo stream,computes parities of the turbo data region, and adds 20-byte longparities.

The duplicator 120 prepares a parity insertion region in the encodedturbo stream according to the coding rate.

The outer encoder 140 carries out encoding, by convolution-encoding theturbo stream, and inserting the encoded value into the parity insertionregion prepared by the duplicator 120.

The outer interleaver 150 outer-interleaves the encoded turbo stream.

The data deinterleaver 160 deinterleaves the interleaved turbo stream.

The MUX 130 multiplexes a separately incoming normal stream and theturbo stream which is processed at the duplicator 120. As a result, amulti TS including mixture of normal stream and turbo stream, isgenerated.

Meanwhile, the MUX 130 may prepare a region for inserting turbo stream,in a stuffing region included in the adaptation field of each packet ofthe multi TS.

The MUX 130 may generate a multi TS including turbo stream includingeach turbo unit varying according to different coding rates, in order totransmit turbo stream having various coding rates and various datarates. The turbo unit may correspond to multiples of 52 packets.

FIG. 11 is a block diagram of a TS generating apparatus according to yetanother exemplary embodiment of the present invention.

Referring to FIG. 11, the TS generating apparatus includes an RS encoder110, a duplicator 120, a MUX 130, a randomizer 170, a turbo processor180 and a derandomizer 190. The RS encoder 110, the duplicator 120 andthe MUX 130 may operate in the same manner as the RS encoder 110, theduplicator 120, and the MUX 130 illustrated in FIG. 4. The explanationregarding overlapping elements or operations will be omitted for thesake of brevity.

The randomizer 170 randomizes the generated multi TS.

The turbo processor 180 performs robust processing, by exclusivelydetecting turbo stream from the randomized multi TS, and encoding andinterleaving the detected turbo stream. The robust turbo stream isdeinterleaved and inserted into the multi TS. As a result, a multi TS isre-constructed.

The turbo processor 180 may be constructed in the manner as illustratedin FIG. 7.

The derandomizer 190 derandomizes the re-constructed multi TS.

FIG. 12 is a block diagram of a transmitting apparatus according to yetanother exemplary embodiment of the present invention.

Referring to FIG. 12, the transmitting apparatus according to yetanother exemplary embodiment of the present invention may include arandomizer 210, an RS encoder 230, a data interleaver 240, a trellisencoder 250, a MUX 260 and a modulator 270.

The transmitting apparatus receives robust multi TS from the TSgenerating apparatus of FIGS. 10 and 11, carries out operationsincluding randomizing, RS encoding data, interleaving, and trellisencoding, multiplexes by adding segment sync and field sync, performschannel modulation and transmits the resultant signal. The constructionof this particular exemplary embodiment is similar to that illustratedin FIG. 8. Therefore, the explanation regarding the overlapping elementsor operations will be omitted for the sake of brevity.

FIG. 13 is a block diagram of the receiving apparatus of FIG. 3according to the exemplary embodiment of the present invention.

Referring to FIG. 13, the receiving apparatus 300 includes a demodulator310, an equalizer 320, a first processor 330, and a second processor340.

If a multi TS is modulated into RF signal format and received via anantenna, the demodulator 310 detects synchronization according to asynchronous signal added to the baseband signal of the received multi TSand performs demodulation.

The equalizer 320 equalizes the demodulated multi TS, and compensatesfor multi-path channel distortion. The multi TS being equalized by theequalizer 320 is provided to the first processor 330 and the secondprocessor 340.

The first processor 330 processes normal stream of the multi TS torecover normal data.

The first processor 330 includes a viterbi decoder 331, a datadeinterleaver 333, an RS decoder 335, and a first derandomizer 337.

The viterbi decoder 331 performs error correction of normal stream ofthe equalized multi TS, performs decryption of the error-correctedsymbol, and outputs symbol packet.

The data deinterleaver 333 deinterleaves the decrypted packet, andrearranges the distributed packets.

The RS decoder 335 corrects an error, by RS decoding the deinterleavednormal stream packets.

The first derandomizer 337 derandomizes the RS decoded normal streampackets, to recover the normal data.

Meanwhile, the second processor 340 processes the turbo stream of themulti TS, to recover the turbo data.

The second processor 340 includes a turbo decoder 341, a secondderandomizer 343 and a turbo stream extractor 345.

The turbo decoder 341 selectively performs turbo-decoding, exclusivelyfor the turbo stream of the equalized multi TS. The turbo-decodinginvolves decoding of turbo stream.

The turbo decoder 341 may perform turbo-decoding, by detecting turbostream from a part of the packet adaptation field or the entire packetadaption field of the multi TS.

The turbo decoder 341 may exclusively decode the data as desired by theuser, according to the coding information.

Because turbo stream is turbo-encoded and deinterleaved in turbo unitsapplying various coding rates, turbo-decoding in turbo units isperformed easily.

Exclusive data decoding according to a user selection is possible. Byexclusively decoding the data desired by a user, a part of the incomingturbo stream, or the entire turbo stream may be selectivelyturbo-decoded.

The second randomizer 343 derandomizes the turbo-decoded multi TS.

The turbo stream extractor 345 recovers turbo data, by detecting turbostream from the derandomized multi TS.

In particular, the turbo stream extractor 345 extracts turbo stream,collects information regarding the turbo stream only, passes the RSdecoder (not shown), and recovers the turbo data.

FIG. 14 is a block diagram of turbo decoder 341.

Referring to FIG. 14, the turbo decoder 341 includes a trellis mapdecoder 410, an outer deinterleaver 420, an outer map decoder 430, andan outer interleaver 440.

The trellis map decoder 410 trellis decodes the turbo stream of theequalized multi TS, and provides the outer deinterleaver 420 with theresultant signal. Exclusive decoding of data of certain channel based onthe coding information is possible according to user selection.

Accordingly, by undergoing the deinterleaving process at the turboprocessor 220 of the transmitting apparatus 200, illustrated in FIG. 6,turbo streams of later distributed multi TS can be combined with eachother, and processing of turbo streams in turbo units is enabled.

The outer deinterleaver 420 deinterleaves the trellis-decoded turbostream.

The outer map decoder 430 may convolution-decode the deinterleaved turbostream. The outer map decoder 430 outputs soft decision output and harddecision output according to the result of the convolution-decoding. Thesoft and hard decisions are based on the metrics of turbo stream.

For example, if the turbo stream has a metric of “0.8”, soft decision“0.8” is output, and if the turbo stream has a metric of “1”, harddecision “1” is output.

The hard decision output from the outer map decoder 430 is provided tothe second derandomizer 343, illustrated in FIG. 13. In this case, thehard decision output refers to the turbo stream.

Meanwhile, if a soft decision is output from the outer map decoder 430,the outer interleaver 440 interleaves the turbo stream and provides thetrellis map decoder 410 with the resultant signal.

The trellis map decoder 410 re-performs trellis decoding of theinterleaved turbo stream, and provides the outer deinterleaver 420 withthe resultant signal. The outer deinterleaver 420 outer-deinterleavesthe signal again, and provides the outer map decoder 430 with theresultant signal.

The operations of the trellis map decoder 410, the outer deinterleaver420, and the outer interleaver 440 may be repeated until a hard decisionoutput is made. As a result, a reliable decoding value can be obtained.

FIG. 15 is a flowchart illustrating the process of transmitting a multiTS according to an exemplary embodiment of the present invention.

Referring to FIG. 15, a multi TS including the mixture of normal streamand turbo stream having variable coding rate, is generated in operationS510. In particular, a parity insertion region is prepared in the turbostream according to various coding rates, and an adaptation field isprepared in the normal stream. The two streams are multiplexed, and as aresult, a multi TS is generated.

Next, the generated multi TS is randomized in operation S520, andturbo-processed in operation S530. The turbo processing will beexplained in detail below, with reference to FIG. 16.

If turbo processing is completed, the multi TS is RS encoded inoperation S540, and interleaved in operation S550.

The interleaved multi TS is trellis encoded, and the trellis encodedmulti TS is added with segment sync and field sync, and then multiplexedin operation S570.

Next, channel modulation is carried out in operation S580. The aboveoperations have been already explained in detail above, and therefore,detailed explanations thereof will be omitted for the sake of brevity.

FIG. 16 is a flowchart illustrating the turbo processing according to anexemplary embodiment of the present invention.

Referring to FIG. 16, a multi TS is received, and turbo stream isdetected exclusively in operation S610. The detected turbo stream isencoded in turbo units in operation S620. The encoding includesconvolution-encoding based on the coding information, and inserting theencoded value in the parity insertion region prepared in the turbostream.

If encoding is completed, the encoded turbo stream is outer-interleavedin operation S630, and the interleaved turbo stream is deinterleaved inoperation S640.

Accordingly, in the later process of interleaving the multi TS, turbostreams of the multi TS can be concentrated with each other. That is,from the viewpoint of receiving apparatus, it is easy to recover turbostream selectively, because the turbo streams are not distributed butcombined with each other. As a result, power consumption at thereceiving apparatus is reduced.

For example, if a user wants to view program 2 only, he may operateturbo 2 only, and not operate the other data, thereby saving powerconsumption.

The turbo stream is inserted back into the multi TS, so that the multiTS is re-constructed in operation S650.

FIG. 17 is a flowchart illustrating the process of receiving a multi TSaccording to an exemplary embodiment of the present invention.

Referring to FIG. 17, a multi TS is received and demodulated inoperation S710. Next, the demodulated stream is equalized in operationS715.

The normal stream of the equalized stream is viterbi-decoded inoperation S720, deinterleaved in operation S725, RS decoded in operationS730, and derandomized and then processed to recover the normal data inoperation S735.

The turbo stream of the equalized stream is selectively decoded first inoperation S740, and derandomized in operation S745. Next, the turbostream is detected from the derandomized multi TS to recover the turbodata in operation S750.

FIG. 18 is a flowchart illustrating a turbo-decoding method according toan exemplary embodiment of the present invention.

Referring to FIG. 18, a turbo stream of a multi TS is trellis-decoded inoperation S810. Exclusive decoding of data of certain channel based onthe coding information is possible, according to user selection.

The trellis-decoded turbo stream is outer-deinterleaved in operationS820, and outer decoding is performed in operation S830.

If a soft decision is output through the outer decoding process, theouter interleaving is performed in operation S840. The outer-interleavedturbo stream then undergoes trellis decoding, and outer deinterleavingin operations S810, S820, respectively. As a result, a reliable harddecision turbo stream can be obtained.

As explained above, according to the exemplary embodiments of thepresent invention, a multi TS including a mixture of a normal stream anda turbo stream having various coding rates can be transmitted andreceived efficiently.

In particular, by encoding and decoding the turbo stream of variablecoding rate in turbo units, a turbo stream of various performances andvarious coding rates can be transmitted and received.

Furthermore, because a turbo stream is processed according to a userselection, power consumption of a receiving apparatus is reduced.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in this embodiment without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. A digital broadcast transmitting system, comprising: a transportstream (TS) generating apparatus which generates a multi TS including atleast one additional data stream processed according to a variablecoding rate of the at least one additional data stream and a normal datastream; and a transmitting apparatus which processes the multi TS, andtransmits the processed multi TS via a channel.
 2. The digital broadcasttransmitting system as claimed in claim 1, wherein the transmittingapparatus processes the at least one additional data stream of the multiTS according to the coding rate.
 3. The digital broadcast transmittingsystem as claimed in claim 1, wherein each of the at least oneadditional data stream has a different coding rate for each turbo unit.4. The digital broadcast transmitting system as claimed in claim 3,wherein each turbo unit contains 52 packets or a multiple of 52 packets.5. The digital broadcast transmitting system as claimed in claim 1,wherein the transmitting apparatus comprises: a randomizer whichreceives the multi TS from the TS generating apparatus and randomizesthe received multi TS; a Reed-Solomon (RS) encoder which RS encodes therandomized multi TS; a data interleaver which interleaves the encodedmulti TS; a trellis encoder which trellis encodes the outer-interleavedmulti TS; a multiplexer (MUX) which carries out multiplexing by adding asegment synchronous signal and a field synchronous signal to thetrellis-encoded multi TS; and a modulator which channel-modulates themultiplexed multi TS, and converts the channel-modulated multiplexedmulti TS into an RF channel band signal.
 6. The digital broadcasttransmitting system as claimed in claim 1, wherein the variable codingrate is a rate of 1/2 or 1/4.
 7. A transport stream (TS) generatingapparatus, comprising: a Reed-Solomon (RS) encoder which RS encodes atleast one additional data stream; a duplicator which performs coding ofeach of the at least one RS-encoded additional data stream according toa variable coding rate of the at least one additional data stream; and amultiplexer (MUX) which multiplexes the at least one additional datastream processed at the duplicator along with a normal data stream, togenerate a multi TS.
 8. The TS generating apparatus as claimed in claim7, wherein each of the at least one additional data stream has adifferent coding rate for each turbo unit.
 9. The TS generatingapparatus as claimed in claim 8, wherein each turbo unit contains 52packets or a multiple of 52 packets.
 10. The TS generating apparatus asclaimed in claim 7, wherein the variable coding rate is a rate of 1/2 or1/4.
 11. A transmission method of a digital broadcast transmittingsystem, comprising: generating a multi transport stream (TS) includingat least one additional data stream processed according to a variablecoding rate of the plurality of additional data streams and a normaldata stream; and processing the multi TS, and transmitting the processedmulti TS via a channel.
 12. The transmission method as claimed in claim11, wherein the processing comprises processing the at least oneadditional data stream of the multi TS according to the coding rate. 13.The transmission method as claimed in claim 11, wherein each of the atleast one additional data stream has a different coding rate for eachturbo unit.
 14. The transmission method as claimed in claim 13, whereineach turbo unit contains 52 packets or a multiple of 52 packets.
 15. Thetransmission method as claimed in claim 11, wherein the transmittingcomprises: receiving the generated multi TS and randomizing the receivedmulti TS; Reed-Solomon (RS) encoding the randomized multi TS;interleaving the encoded multi TS; trellis encoding theouter-interleaved multi TS; multiplexing by adding a segment synchronoussignal and a field synchronous signal to the trellis-encoded multi TS;and channel-modulating the multiplexed multi TS, and converting thechannel-modulated multiplexed multi TS into an RF channel band signal.16. The transmission method as claimed in claim 11, wherein the variablecoding rate is a rate of 1/2 or 1/4.
 17. A transport stream (TS)generating method, comprising: a Reed-Solomon (RS) encoding at least oneadditional data stream; coding each of the at least one RS-encodedadditional data stream according to a variable coding rate of the atleast one RS-encoded additional data stream; and multiplexing the atleast one coded additional data stream along with a normal data stream,to generate a multi TS.
 18. The TS generating method as claimed in claim17, wherein each of the at least one additional data stream has adifferent coding rate for each turbo unit.
 19. The TS generating methodas claimed in claim 18, wherein each turbo unit contains 52 packets or amultiple of 52 packets.
 20. The TS generating method as claimed in claim17, wherein the variable coding rate is a rate of 1/2 or 1/4.